The present invention relates to continuous filament nonwoven webs.
There exist a variety of processes for forming continuous filament nonwoven webs. The spunbond fiber process is one example. Generally speaking, methods for making spunbond fiber nonwoven webs include extruding molten thermoplastic polymer through a spinneret and drawing the extruded polymer into filaments to form a web of randomly arrayed fibers on a collecting surface. As examples, methods for making the same are described in U.S. Pat. No. 4,692,618 to Dorschner et al., U.S. Pat. No. 4,340,563 to Appel et al. and U.S. Pat. No. 3,802,817 to Matsuki et al. A second and distinct process for making continuous filament nonwoven webs is the meltblowing process. Meltblown fiber webs are generally formed by extruding a molten thermoplastic material through a plurality of fine die capillaries as molten threads or filaments into converging high velocity air streams which attenuate the filaments of molten thermoplastic material to reduce their diameter. Thereafter, the meltblown fibers are deposited on a collecting surface to form a web of randomly dispersed meltblown fibers. Meltblown fiber processes are disclosed in, by way of example only, U.S. Pat. No. 3,849,241 to Butin et al., U.S. Pat. No. 5,160,746 to Dodge et al., and U.S. Pat. No. 4,526,733 to Lau.
Continuous filament nonwoven webs have found industrial applicability in a wide range of products and/or uses. As examples, continuous filament nonwoven webs have heretofore been used as filtration and/or barrier type materials such as in facemasks, sterilization wraps, HVAC media, surgical gowns, industrial workwear and so forth. Additionally, continuous filament nonwoven webs have been widely used as one or more components of personal care products. As examples, continuous filament nonwoven webs have been used in a variety of components ranging from liquid distribution layers, composite absorbent materials, baffles, coverstock and so forth. However, while continuous filament nonwovens have found wide acceptance within various industries the demands upon the physical attributes and/or performance of existing materials continues to increase. In addition, by improving the physical attributes and/or performance of continuous filament nonwoven materials the materials can be utilized in still a wider array of applications and products.
Thus, there exists a need for continuous filament nonwoven webs having improved and/or specialized physical attributes and functionality. More particularly, there exists a need for specialized continuous filament nonwoven webs having improved liquid handling properties, treatment retention and location, hand (i.e. softness), resiliency, durability, stretch-recovery and/or other desirable properties.
The aforesaid needs are fulfilled and the problems experienced by those skilled in the art overcome by nonwoven webs of the present invention comprising a unitary continuous filament nonwoven web comprising a composite of at least first and second continuous filaments. In one aspect of the present invention, the continuous filament nonwoven web can comprise a first region comprising first filaments and a second region comprising second filaments wherein the first and second filaments are different from one another. The first and second regions can extend adjacent one another in the machine direction. Further, the first and second filaments can be entangled or mixed adjacent the inter-face between the first and second region. In a further aspect of the invention, the composite nonwoven web can comprise a region of first continuous filaments, a region of second continuous filaments and a region of third continuous filaments each extending substantially continuously in the machine direction. The second region can thus be a discrete region positioned between the first and third regions. The second continuous filaments are distinct from the first and third continuous filaments and the first and third filaments can be the same or different from one another.